Alloying techniques of mixing plural polymers different in characteristics have been investigated in order to exhibit characteristics of such plurality of polymers effectively. In this polymer alloy, plural polymers being incompatible with each other are generally employed, and the resultant polymer alloy constitutes a heterogenous polymer system.
On the other hand, a heterogenous polymer system comprising plural polymers is usually poor in mechanical characteristics such as impact resistance, strength (steeliness) or the like. Accordingly, a polymer containing unit(s) as the same with, or similar to, the constituent units of the plural polymers are usually added in the polymer alloy. By way of illustration, Japanese Patent Application Laid-open No. 76743/1991 (JP-A-3-76743) discloses a thermoplastic resin composition containing a composition comprising a specific engineering plastic and a rubber-reinforced styrenic resin, and an oxazoline-modified copolymer as produced from vinyloxazoline, an aromatic vinyl monomer and other vinyl monomer.
Further, Japanese Patent Application Laid-open No. 172347/1991 (JP-A-3-172347) discloses a thermoplastic resin composition comprising a polyester, an aromatic vinyl polymer having a functional group and a polycarbonate, while the aromatic vinyl polymer has been obtained by copolymerizing a monomer having vinyloxazoline or glycidyl group, and styrene.
Japanese Patent Application Laid-open No. 255857/1990 (JP-A-2-255857) discloses an aromatic polycarbonate composition comprising an aromatic polycarbonate resin and a functional elastic polymer. This functional elastic polymer contains a reaction product derived from an ethylene elastomer having a reactive group and a polystyrene functionalized by an oxazoline.
The oxazoline-modified copolymer and the like described in these literatures are useful for alloying specific polymers. However, the use the oxazoline-modified copolymer, for example, can only be applied for alloying polymers being categorized to a narrow range, and it is difficult to alloying the polymers by using a small amount of the compound.
Japanese Patent Application Laid-open No. 184224/1994 (JP-A-6-184224) discloses a method of producing a compatibilizing agent which comprises allowing a polymer having, in a terminal or side chain of a hydrophobic main chain, a functional group containing an active hydrogen atom, such as carboxyl group (e.g. a modified olefinic polymer), to react with an oxazoline. The compatibilizing agent obtained by this method is serviceable for obtaining a polymer alloy by adding the same in a small amount to a polymer composition comprising plural polymers incompatible with each other. It is necessary, however, to allow the polymer having a functional group containing an active hydrogen atom to previously react with an oxazoline for obtaining the compatibilizing agent. Accordingly, there is possibility that choiceable or selectable range of the polymer and the oxazoline would narrow in the design of the compatibilizing agent, and a composition containing polymers incompatible with each other can hardly be compatibilized economically in a simple and easy manner.
It is also proposed that scrap polymers incompatible with each other (e.g. a polyester and a polyamide) which have been degraded in molecular weights due to time-series change or hydrolysis are reutilized as a compatible system by allowing the scrap resins to react with bis-2-oxazoline to convert a block copolymer. This reaction is based on the use of an ester amide bond of an oxazoline group of the bis-2-oxazoline and terminal carboxyl groups in 2 or more molecular chains to give a high molecular weight polymer ("Plastic Age", 114-118, March 1995). British Patent No. 1426409 proposes a process of modifying a polyester by adding a bisoxazoline to a polyester with a high molecular weight having a carboxyl group, in order to inhibit decomposition of the polyester and decrease of its molecular weight in a melting-extruding step for spinning. These literatures, however, fail to describe a process of utilizing a bis-2-oxazoline compound as a compatibilizing agent. Further, since the resin has a high molecular weight, it is difficult to alloy plural polymers incompatible with each other by adding a small amount of the reaction product.